1. Field of the Invention
The present invention relates to a boring tool and, in particular, to a hand-held boring tool having a housing part, means for transmitting a rotational movement to a borer, with the transmitting means being supported in the housing part and having a central receiving region for receiving the borer, and two, spaced from each other, bearing members for supporting the transmitting means in the housing part.
2. Description of the Prior Art
For forming bores in hardened structural components for attachment anchors or for passing tubes therethrough, boring tools which are employed with borers equipped with diamond bits, are used. Such a boring tool is disclosed, e.g., in German Patent No. 3,434,261. The known boring tool includes an electrical drive unit and a borer receiving fixture. The borer receiving fixture has a central receiving region for receiving the borer shank and is supported in a housing part with two, spaced from each other, bearing members. In the known boring tool, both the longitudinal axis of the borer receiving fixture and the longitudinal axis of the borer are arranged coaxially with the longitudinal axis of the housing part. In the boring tools and, in particular, in the handheld boring tools, because of the required high pressure forces and a relative long time, necessary for forming a bore, the borer is subjected to high stresses. The pressure forces are distributed over the entire end surface of the cutting region of the borer facing in the bore-forming direction so that only a small surface pressure is achieved, and the projecting diamonds penetrate into the structural component to a small degree and can be stripped off. Because of their small penetration into the structural component, the diamond tips become rounded, and the entire boring process worsens. The boring speed is very low.
Accordingly, an object of the present invention is a boring tool with which higher boring speeds can be achieved while the applied pressure force is small.